Field of the Invention
This invention relates to medical devices. It is particularly directed to a multi-use tourniquet for exemplary use in phlebotomy.
State of the Art
It is known in the field of phlebotomy to apply an elastic membrane tourniquet to resist flow of venous blood prior to drawing a blood sample using, for example, a syringe and needle. One such ubiquitous tourniquet consists of a membrane-like band of rubber-like material that is less than about 1/16 inches in thickness, about 1 inch wide, and about 18 inches long. Application of the tourniquet improves needle access to the target vein, and facilitates collection of an ample blood sample in short order.
The ubiquitous phlebotomy tourniquet is conventionally applied to a human limb, e.g. an arm, by wrapping the band in stretched condition around the circumference of the arm to over-wrap and thereby trap a first end of the band against the arm. The over-wrapping portion of the band essentially anchors the trapped end using friction and compression of the trapped first end against the skin. A stretched condition may be conveniently maintained in an encircling portion of the band by twisting and tucking a proximal end portion under a retention wrap of the band effective to hold the proximal end portion at a second anchored position. Again, compression from the encircling portion and friction hold the second end in an installed position. The stretched and anchored band compresses onto the skin around the circumference of the arm, and resists flow of venous blood. Typically, a tail of the band's second end is arranged to protrude from under the retention wrap to facilitate removal of the anchored proximal portion from under the retention wrap. A yank on the tail can extract the tucked portion from under the retaining wrap.
After a medical procedure (e.g., a blood draw) is performed, the tourniquet may be removed by simply pulling on the protruding tail, and a bandage is applied to the sample access wound. A conventional bandage includes an adhesive strip sized between perhaps about 3 and about 6 inches in length and about 1 to 2 inches in width that is applied directly to the skin of the patient. The length generally extends partially around the circumference of the arm, and the strip is typically applied in a state of tension to place compression onto the wound. Conventionally, pressure is also applied by the patient for a period of time to assist in wound closing.
The above-described ubiquitous phlebotomy tourniquet was conventionally re-used a plurality of times, on a plurality of different patients. Essentially, the tourniquet band was re-used until its resiliency deteriorated to an ineffective condition. However, a change in best medical practice many years ago (with respect to the filing date of this document) required that such medical tools be used on only a single patient, and then discarded. It is believed that single-patient use was promulgated to avoid cross-contamination between patients.
There are undesirable effects resulting from the above-described conventional phlebotomy treatment that have been long-known, and unresolved by others. For example, removing the adhesive strip from a patient's skin can be painful, and even traumatic. In the case of certain elderly individuals, removal of the adhesive strip can actually tear the skin. Sometimes, application of operable pressure is not maintained for a sufficient length of time, resulting in blood loss and/or extensive bruised-appearing areas or blood clots. Adhesive on the bandage strip may cause an allergic reaction. If the conventional tourniquet described above is applied to additionally compress the wound, an elderly patient may not be able to remove it, due to low hand strength, or other reason. Long-term application of a tourniquet can be fatal to extremity tissues.
Tourniquets of various sorts are known. Such devices operate to resist flow of blood through a portion of a body circumscribed by the device, typically an extremity. Even a simple rope, or other relatively non-elastic member, may suffice as an operable tourniquet. In use of non-elastic devices, such as a length of rope, a compression must be induced by an external operator. For example, a stick may be inserted into a loop of rope, and the stick may be rotated to cause the rope to wind up, and thereby compress an encircled extremity. An external operator is required to maintain an effective compression on the encircled body portion. For example, tucking a second end of rope under an encircling portion of rope would be inoperable to maintain a sufficient compression around an encircled extremity, because the non-elastic rope does not inherently produce a sufficient self-biased constriction.
A commercially available alternative tourniquet that is characterized as being non-elastic includes a plastic strap similar to an industrial-sized zip tie. That device is advertised on the internet for military use as a tourniquet. The plastic strap that carries the teeth is not very elastic and stretchy (e.g. is probably subject to plastic deformation or damage beyond less than 10% elongation). Tension applied to the strap basically compresses tissues directly, and those tissues generate the tension bias remaining in the strap after its installation. Such a tourniquet is tightened in a ratchet-like fashion, by pulling the end through an opening carried at one end, and teeth disposed along the length of the band are successively engaged by a pawl associated with the opening. Friction between the plastic band segments would be inoperable to maintain an effective tension in the band if a proximal portion were tucked under an encircling length of the band, similar to a conventional phlebotomy procedure. It is not clear that the plastic band could even be manipulated to form the conventional twist-and-tuck-under proximal portion to expose a tail end. It is believed that the plastic band must be cut with a tool to remove the tourniquet from the patient's extremity. In short, the known tourniquets are incapable of performing certain desired actions.